Leviticus 13:6-8

6And the priest shall look on him again the seventh day, and behold, the sore is become pale and the sore hath not spread in the skin, then the priest shall pronounce him clean; it is a scab; and he shall wash his garments and be clean.

7But if the scab have spread much in the skin, after that he hath been seen by the priest for his cleansing, he shall be seen by the priest again;

8and the priest shall look on him, and behold, the scab hath spread in the skin; then the priest shall pronounce him unclean: it is leprosy.